This invention relates to rotary drilling apparatus and more particularly to a casing tong used in disconnecting a drill pipe from the drill string or from the drill bit. More particularly, this invention relates to an adjustable casing tong assembly and pivoting arm for disassembling sections of pipe in a manner such that the casing tong can match the angle of the pipe when positioned at an angle for angle hole drilling purposes.
The pivoting of pipe tong devices when handling drill pipes as well as their rotation is known. For example, U.S. Pat. No. 2,871,743 of Kelley shows heads 30 and 30a which can be rotated 180.degree. by means of moving a latch pin 32. Pivoting is afforded through a wrist pin 45 supported on a pedestal structure 10. A racking mechanism is described in U.S Pat. No. 3,177,944 of Knights which has boom type arms 61 and 67 to provide support for tongs 72 which are actuated by a hydraulic jack 85. U.S. Pat. Nos. 3,316,783 and 3,500,708 issued to Wilson show power actuated tongs with multiple arm and pivotal actuation members. U.S. Pat. No. 3,780,815 of Barron shows a vertically disposed column 10 with a power tong assembly 26 supported by a yoke structure 24 which extends from the support collar 20 for movement up and down the column.
The prior art does not address the problem of angle drilling wherein pipe must be handled for breakout purposes at an angle with respect to the mast when the mast is positioned for angle drilling. Specifically, the prior art does not provide multiple adjustments for a casing tong which not only is adjustable along the support column but also includes pin indexing means for matching the angle of the drill pipe.
It is an advantage of the present invention to provide a casing tong which is adjustable to match the angle of the drill pipe during angle drilling.
It is another advantage of this invention to provide a casing tong of the previously described type which is especially adapted for use with blast hole drills.
Still another advantage of this invention is to provide a casing tong of the foregoing type which not only is adjustable along a vertical support column but also includes pin indexing means for further adjustment purposes.
Yet another advantage of this invention is to provide a casing tong for use when the drill pipe and mast are at an angle but will allow the operator to stand on a level deck surface rather than the angled surface of the mast structure.
Other advantages are an adjustable casing tong which can be manufactured from readily available components and utilized by an operator with a minimum of effort.